<\/span><\/h3>\n\n\n\n\u5b66\u751f\u8868S(SNO,SNAME,AGE,SEX)\uff0c\u5176\u5c5e\u6027\u5206\u522b\u8868\u793a\u5b66\u53f7\u3001\u5b66\u751f\u59d3\u540d\u3001\u5e74\u9f84\u3001\u6027\u522b\uff1b<\/p>\n\n\n\n
gbase> create table student(sno varchar(20),sname varchar(20),age int, sex int);\nQuery OK, 0 rows affected (Elapsed: 00:00:00.12)\n\ngbase> insert into student values ('20210001','\u5f20\u4e09','18',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.07)\n\ngbase> insert into student values ('20210002','\u674e\u56db','19',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.05)\n\ngbase> insert into student values ('20210003','\u738b\u4e94','18',0);\nQuery OK, 1 row affected (Elapsed: 00:00:00.06)\n\ngbase> insert into student values ('20210004','\u8d75\u516d','18',0);\nQuery OK, 1 row affected (Elapsed: 00:00:00.06)\n\ngbase> select * from student;\n+----------+--------+------+------+\n| sno | sname | age | sex |\n+----------+--------+------+------+\n| 20210001 | \u5f20\u4e09 | 18 | 1 |\n| 20210002 | \u674e\u56db | 19 | 1 |\n| 20210003 | \u738b\u4e94 | 18 | 0 |\n| 20210004 | \u8d75\u516d | 18 | 0 |\n+----------+--------+------+------+\n4 rows in set (Elapsed: 00:00:00.01)\n<\/code><\/pre>\n\n\n\n<\/span>\u8bfe\u7a0b\u8868(course)<\/span><\/h3>\n\n\n\n\u8bfe\u7a0b\u8868C(CNO,CNAME,TEACHER)\uff0c\u5176\u5c5e\u6027\u5206\u522b\u8868\u793a\u8bfe\u7a0b\u53f7\u3001\u8bfe\u7a0b\u540d\u3001\u4e0a\u8bfe\u6559\u5e08\u540d\uff1b<\/p>\n\n\n\n
gbase> create table course(cno varchar(10),cname varchar(20),teacher varchar(20));\nQuery OK, 0 rows affected (Elapsed: 00:00:00.10)\n\ngbase> insert into course values('990001','\u5927\u6570','\u5f20\u8001\u5e08');\nQuery OK, 1 row affected (Elapsed: 00:00:00.07)\n\ngbase> insert into course values('990002','\u5927\u82f1','\u674e\u8001\u5e08');\nQuery OK, 1 row affected (Elapsed: 00:00:00.04)\n\ngbase> select * from course;\n+--------+--------+-----------+\n| cno | cname | teacher |\n+--------+--------+-----------+\n| 990001 | \u5927\u6570 | \u5f20\u8001\u5e08 |\n| 990002 | \u5927\u82f1 | \u674e\u8001\u5e08 |\n+--------+--------+-----------+\n2 rows in set (Elapsed: 00:00:00.01)\n<\/code><\/pre>\n\n\n\n<\/span>\u9009\u4fee\u8868(student_course)<\/span><\/h3>\n\n\n\n\u9009\u4fee\u8868SC(SNO,CNO,GRADE)\uff0c\u5176\u5c5e\u6027\u5206\u522b\u8868\u793a\u5b66\u53f7\u3001\u8bfe\u7a0b\u53f7\u3001\u6210\u7ee9\u3002<\/p>\n\n\n\n
gbase> create table student_course(sno varchar(20),cno varchar(10),grade int);\nQuery OK, 0 rows affected (Elapsed: 00:00:00.11)\n\ngbase> insert into student_course values ('20210001','990001',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.07)\n\ngbase> insert into student_course values ('20210002','990001',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.05)\n\ngbase> insert into student_course values ('20210003','990001',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.05)\n\ngbase> insert into student_course values ('20210004','990001',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.07)\n\ngbase> insert into student_course values ('20210002','990002',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.08)\n\ngbase> insert into student_course values ('20210003','990002',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.04)\n\ngbase> insert into student_course values ('20210004','990002',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.05)\n\ngbase> select * from student_course;\n+----------+--------+-------+\n| sno | cno | grade |\n+----------+--------+-------+\n| 20210001 | 990001 | 1 |\n| 20210002 | 990001 | 1 |\n| 20210003 | 990001 | 1 |\n| 20210004 | 990001 | 1 |\n| 20210002 | 990002 | 1 |\n| 20210003 | 990002 | 1 |\n| 20210004 | 990002 | 1 |\n+----------+--------+-------+\n7 rows in set (Elapsed: 00:00:00.01)\n<\/code><\/pre>\n\n\n\n<\/span>\u67e5\u8be2\u5f20\u4e09\u540c\u5b66\u6ca1\u6709\u9009\u4fee\u7684\u8bfe\u7a0b\u7684\u8bfe\u7a0b\u53f7<\/span><\/h2>\n\n\n\n<\/span>Analyse<\/span><\/h3>\n\n\n\n\u5f20\u4e09\u6ca1\u6709\u9009\u4fee = \u6240\u6709\u8bfe\u7a0b - \u5f20\u4e09\u5df2\u7ecf\u9009\u4fee\u7684\u3002<\/p>\n\n\n\n
<\/span>SQL\u5b9e\u73b0<\/span><\/h3>\n\n\n\n<\/span>\u5f20\u4e09\u9009\u4fee\u7684\u8bfe\u7a0b<\/span><\/h4>\n\n\n\n\u901a\u8fc7\u540d\u5b57\uff0c\u4ece\u5b66\u751f\u8868(student)\uff0c\u53ef\u4ee5\u67e5\u8be2\u5230\u5176\u5b66\u751f\u7f16\u53f7\uff0c\u518d\u4ece\u5b66\u751f\u7f16\u53f7\uff0c\u4ece\u9009\u4fee\u8bfe\u7a0b\u8868\u91cc\uff0c\u83b7\u5f97\u5176\u5df2\u7ecf\u9009\u4fee\u7684\u8bfe\u7a0b\u5217\u8868\u3002\u672c\u5904\u4f7f\u7528\u4e86\u4e00\u4e2a\u5b50\u67e5\u8be2\u3002<\/p>\n\n\n\n
gbase> select * from student_course where sno=(select sno from student where sname='\u5f20\u4e09');\n+----------+--------+-------+\n| sno | cno | grade |\n+----------+--------+-------+\n| 20210001 | 990001 | 1 |\n+----------+--------+-------+\n1 row in set (Elapsed: 00:00:00.05)\n<\/code><\/pre>\n\n\n\n<\/span>\u5f20\u4e09\u6ca1\u6709\u9009\u4fee\u7684\u8bfe\u7a0b<\/span><\/h4>\n\n\n\n\u901a\u8fc7\u8bfe\u7a0b\u8868\uff0c\u67e5\u8be2 cno not in \u5df2\u7ecf\u9009\u4fee\u7684\u8bfe\u7a0b\u4fe1\u606f\uff0c\u62ff\u5230\u6ca1\u6709\u9009\u4fee\u7684\u8bfe\u7a0b\u3002<\/p>\n\n\n\n
gbase> select * from course where cno not in (select cno from student_course where sno=(select sno from student where sname='\u5f20\u4e09'));\n+--------+--------+-----------+\n| cno | cname | teacher |\n+--------+--------+-----------+\n| 990002 | \u5927\u82f1 | \u674e\u8001\u5e08 |\n+--------+--------+-----------+\n1 row in set (Elapsed: 00:00:00.05)\n\ngbase> select cno from course where cno not in (select cno from student_course where sno=(select sno from student where sname='\u5f20\u4e09'));\n+--------+\n| cno |\n+--------+\n| 990002 |\n+--------+\n1 row in set (Elapsed: 00:00:00.04)<\/code><\/pre>\n\n\n\n<\/span>\u5982\u679c\u5f20\u4e09\u5b58\u5728\u91cd\u540d\u5462\uff1f<\/span><\/h2>\n\n\n\n<\/span>\u6570\u636e\u53d8\u52a8<\/span><\/h3>\n\n\n\n\u6211\u4eec\u589e\u52a0\u4e86\u4e00\u4e2a\u5b66\u751f\uff0c\u4e5f\u53eb\u5f20\u4e09\uff0c\u5176cno=20210099, \u540c\u65f6\u8be5\u5b66\u751f\u548c\u524d\u4e00\u4e2a\u5f20\u4e09\u4e0d\u540c\uff1a\u9009\u4fee\u4e86\u7b2c\u4e00\u4e2a\u8bfe\u7a0b\uff0c\u800c\u6ca1\u6709\u9009\u62e9\u7b2c\u4e8c\u4e2a\u8bfe\u7a0b\u3002<\/p>\n\n\n\n
gbase> insert into student values ('20210099','\u5f20\u4e09','18',0);\nQuery OK, 1 row affected (Elapsed: 00:00:00.07)\n\ngbase> insert into student_course values ('20210099','990002',1);\nQuery OK, 1 row affected (Elapsed: 00:00:00.05)\n\ngbase> select * from student;\n+----------+--------+------+------+\n| sno | sname | age | sex |\n+----------+--------+------+------+\n| 20210001 | \u5f20\u4e09 | 18 | 1 |\n| 20210002 | \u674e\u56db | 19 | 1 |\n| 20210003 | \u738b\u4e94 | 18 | 0 |\n| 20210004 | \u8d75\u516d | 18 | 0 |\n| 20210099 | \u5f20\u4e09 | 18 | 0 |\n+----------+--------+------+------+\n5 rows in set (Elapsed: 00:00:00.00)\n\ngbase> select * from course;\n+--------+--------+-----------+\n| cno | cname | teacher |\n+--------+--------+-----------+\n| 990001 | \u5927\u6570 | \u5f20\u8001\u5e08 |\n| 990002 | \u5927\u82f1 | \u674e\u8001\u5e08 |\n+--------+--------+-----------+\n2 rows in set (Elapsed: 00:00:00.01)\n\ngbase> select * from student_course;\n+----------+--------+-------+\n| sno | cno | grade |\n+----------+--------+-------+\n| 20210001 | 990001 <\/strong>| 1 |<\/span>\n| 20210002 | 990001 | 1 |\n| 20210003 | 990001 | 1 |\n| 20210004 | 990001 | 1 |\n| 20210002 | 990002 | 1 |\n| 20210003 | 990002 | 1 |\n| 20210004 | 990002 | 1 |\n| 20210099 | 990002 <\/strong>| 1 |<\/span>\n+----------+--------+-------+\n8 rows in set (Elapsed: 00:00:00.01)\n\n<\/code><\/pre>\n\n\n\n<\/span>\u76f4\u63a5\u67e5\u8be2\u62a5\u9519<\/span><\/h3>\n\n\n\n\u7531\u4e8e\u53eb\u5f20\u4e09\u7684\u6709\u591a\u4e2a\uff0c\u6240\u4ee5\u524d\u4e00\u4e2a\u5b9e\u73b0SQL\u91cc\u9762\u7684cno=\u5b50\u67e5\u8be2\u4f1a\u56e0\u4e3a1\u5bf9\u591a\uff0c\u800c\u62a5\u9519\u3002\u5728GBase 8a\u6570\u636e\u5e93\u62a5\u9519\u6837\u4f8b\u5982\u4e0b<\/p>\n\n\n\n
gbase> select cno from course where cno not in (select cno from student_course where sno=(select sno from student where sname='\u5f20\u4e09'));\nERROR 1708 (HY000): [10.0.2.101:5050](GBA-02AD-0005)Failed to query in gnode:\nDETAIL: (GBA-01EX-0002) Subquery return more than 1 row\nSQL: SELECT \/<\/code><\/pre>\n\n\n\n<\/span>\u7b49\u4e8e\u6539\u7528in\uff0c\u7ed3\u679c\u9519\u8bef<\/span><\/h3>\n\n\n\n\u7531\u4e8e2\u4eba\u5206\u522b\u9009\u62e9\u4e86\u4e0d\u540c\u7684\u9009\u4fee\uff0c\u5bfc\u81f4\u7ed3\u679c\u4e3a\u7a7a\u3002<\/p>\n\n\n\n
gbase> select cno from course where cno not in (select cno from student_course where sno in(select sno from student where sname='\u5f20\u4e09'));\nEmpty set (Elapsed: 00:00:00.04)<\/code><\/pre>\n\n\n\n<\/span>\u6539\u8fdb\u65b9\u6848<\/span><\/h3>\n\n\n\n\u867d\u7136\u90fd\u53eb\u5f20\u4e09\uff0c\u4f46\u5176\u5b66\u53f7\u80af\u5b9a\u4e0d\u540c\uff0c\u6240\u4ee5\u6700\u7ec8\u7ed3\u679c\uff0c\u5fc5\u7136\u662f\u6839\u636e\u5b66\u53f7\uff0c\u800c\u4e0d\u662f\u6839\u636e\u59d3\u540d\u6765\u533a\u5206\u3002<\/p>\n\n\n\n
<\/span>\u62ff\u5230\u5f20\u4e09\u80fd\u9009\u4fee\u7684\u8bfe\u7a0b\u5217\u8868<\/span><\/h4>\n\n\n\n\u901a\u8fc7\u7b1b\u5361\u5c14\uff0c\u65e0\u6761\u4ef6\u7684join,\u5f97\u5230\u5f20\u4e09\u80fd\u9009\u4fee\u7684\u6240\u6709\u8bfe\u7a0b\u5bf9\u7167\u8868\u3002\u5176\u4e2d\u5305\u542b\u4e86\u6240\u6709\u53eb\u5f20\u4e09\u7684\u4eba\u3002<\/p>\n\n\n\n
gbase> select * from student s,course c where s.sname='\u5f20\u4e09';\n+----------+--------+------+------+--------+--------+-----------+\n| sno | sname | age | sex | cno | cname | teacher |\n+----------+--------+------+------+--------+--------+-----------+\n| 20210001 | \u5f20\u4e09 | 18 | 1 | 990001 | \u5927\u6570 | \u5f20\u8001\u5e08 |\n| 20210001 | \u5f20\u4e09 | 18 | 1 | 990002 | \u5927\u82f1 | \u674e\u8001\u5e08 |\n| 20210099 | \u5f20\u4e09 | 18 | 0 | 990001 | \u5927\u6570 | \u5f20\u8001\u5e08 |\n| 20210099 | \u5f20\u4e09 | 18 | 0 | 990002 | \u5927\u82f1 | \u674e\u8001\u5e08 |\n+----------+--------+------+------+--------+--------+-----------+\n<\/code><\/pre>\n\n\n\n<\/span>\u5173\u8054\u8bfe\u7a0b\u8868<\/span><\/h4>\n\n\n\n\u5de6\u5173\u8054\u8bfe\u7a0b\u8868\uff0c\u53ef\u4ee5\u53d1\u73b0\u6709\u6ca1\u6709\u5173\u8054\u4e0a\u7684\u3002<\/p>\n\n\n\n
gbase> select * from (select s.sno,c.cno from student s,course c where s.sname='\u5f20\u4e09')t left join student_course sc on sc.sno=t.sno and sc.cno=t.cno;\n+----------+--------+----------+--------+-------+\n| sno | cno | sno | cno | grade |\n+----------+--------+----------+--------+-------+\n| 20210001 | 990001 | 20210001 | 990001 | 1 |\n| 20210099 | 990002 | 20210099 | 990002 | 1 |\n| 20210001 | 990002 | NULL | NULL | NULL |\n| 20210099 | 990001 | NULL | NULL | NULL |\n+----------+--------+----------+--------+-------+\n4 rows in set (Elapsed: 00:00:00.04)\n<\/code><\/pre>\n\n\n\n<\/span>\u5f20\u4e09\u6ca1\u6709\u9009\u4fee\u7684\u8bfe\u7a0b<\/span><\/h4>\n\n\n\n\u901a\u8fc7\u8fc7\u6ee4\u8bfe\u7a0b\u8868\u91ccnull\u7684\u6570\u636e\uff0c\u5c31\u662f\u6ca1\u6709\u9009\u4fee\u7684\u8bfe\u7a0b\u4e86\u3002<\/p>\n\n\n\n
gbase> select t.sno,t.cno from (select s.sno,c.cno from student s,course c where s.sname='\u5f20\u4e09')t left join student_course sc on sc.sno=t.sno and sc.cno=t.cno where sc.sno is null;\n+----------+--------+\n| sno | cno |\n+----------+--------+\n| 20210001 | 990002 |\n| 20210099 | 990001 |\n+----------+--------+\n2 rows in set (Elapsed: 00:00:00.06)<\/code><\/pre>","protected":false},"excerpt":{"rendered":"\u672c\u6587\u662f\u4e00\u9053\u7f51\u4e0a\u7684\u9762\u8bd5\u9898\u76ee\uff0c\u67e5\u8be2\u67d0\u4f4d\u540d\u5b57\u53eb\u201c\u5f20\u4e09\"\u7684\u5b66\u751f\uff0c\u6709\u54ea\u4e9b\u8bfe\u7a0b\u6ca1\u6709\u9009\u4fee\u3002\u8981\u8003\u8651\u5230\u59d3\u540d\u91cd\u590d\u7684\u53ef\u80fd\u6027\u3002<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[81],"class_list":["post-7540","post","type-post","status-publish","format-standard","hentry","category-gbase8a","tag-81"],"_links":{"self":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/7540","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/comments?post=7540"}],"version-history":[{"count":17,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/7540\/revisions"}],"predecessor-version":[{"id":7567,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/7540\/revisions\/7567"}],"wp:attachment":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/media?parent=7540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/categories?post=7540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/tags?post=7540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}